DE 10 2004 026 105 A1 discloses an air filter for an internal combustion engine. The air filter comprises a filter element. In order to filter air, an air stream hits the filter element from below, passes the filter element and leaves it from its upper surface. The air filter has a flat structure so that it can be mounted on top of the internal combustion engine.
WO 2011/076586 A1 shows an air filter with a gasket. The gasket seals a filter element of the air filter to a filter housing of the air filter.
WO 2013/093685 A1 discloses an air filter for an internal combustion engine. The air filter has a filter housing. In the filter housing a filter element separates a dirty air side from a clean air side. The filter housing has a channeling section with an inlet and outlet for the air and a filter section with the filter element. The filter element is sealed to the clean air side via a filter section of the gasket. The gasket furthermore has a channeling section for sealing the channeling section of the housing. Channeling section and filter section of the gasket share a common section.
FR 2 922 269 A1, U.S. Pat. No. 4,861,359 and EP 1 433 947 A2 respectively show a similar air filter with a gasket for covering two sections of a filter housing.
DE 10 2010 020 261 A1 discloses an air filter with a gasket. The gasket covers three openings of the air filter.
US 2004/0011010 A1 shows an air filter and a corresponding filter element for use in an internal combustion engine. The air filter has an intake silencing chamber, where external air is input and passed to a filter element. The intake silencing chamber is sealed by a gasket of the filter element.
Finally, EP 0 534 079 A2 discloses an air filter with a gasket. A main part of the gasket seals a filter element on top of an inlet chamber of a filter housing. An additional part of the gasket seals an outlet chamber of the filter housing. Inlet chamber and outlet chamber are separated by a separation wall. The main part of the gasket shares a common bridge with the additional part of the gasket, whereby the bridge is put on the separation wall.
The gaskets of the aforementioned filter element units provide the same cross-section for both parts of the gasket. The gaskets known in the art are thus inflexible in terms of their application to different channels of the air filter. For example, the gasket might be applied to provide radial sealing properties to a first channel and axial sealing properties to a second channel. Such different sealing properties up to now are not provided by a single gasket with homogeneous cross section and two openings, but only by two different individual gaskets. However, two different individual gaskets need to be installed in an elaborate way.